More recently we revealed that the strict restriction of
the resulting ISP formalism
to the \(K=3\)  kinematical scenario given by Eq. (REF )
was in fact based on an elementary misunderstanding.
We felt discouraged by the
apparently counterintuitive
observation that at \(K=3\)  the parity \({\cal P}=Z_2\) 
seems to have lost its physical observability status.
Only later we imagined that such a loss is in
fact mathematically very natural, especially when one
builds the models without some suitable ad hoc 
additional constraints (see, e.g., an
extensive discussion of this point in [1]}).
